Seiko 6105-8110 "A"

Case Diameter: 44mm
Case Height: 12.5 mm
Case length: 47.5mm
Lug Width: 19 mm
Movement: Seiko 6105A 17 jewel
hacking automatic. 21,600 bph,
quick-set date
Case material: Stainless steel
Crown: Non-screw-down
Bezel: Bi-directional, indexed
w/ 60 clicks
Water resistance: 150 meters
Vintage: 1973

The cal. 6105 movement comes in 2 variations -- 6105A and 6105B. They are both 17J and run at 21,600 bph. They have a quickset date-only calendar mechanism.

The 6105-8000 and 6105-8009 models use the cal. 6105A movement and have symmetrical cushion cases. The 6105-8110 and 6105-8119 models come later and use the cal. 6105B movement and have larger asymmetical cushion cases.

This is the "later" of two 6105 series divers made by Seiko and differs from the first by having a larger, asymmetrical cushion case and the 6105B movement.

From comments made by owners of 6105 divers, it seems that are 6105 movements that hack and there are some that do not. In a S&C Forum post, "ed jacobson" says, "The first series 6105 does not hack. The dial is signed 'waterproof'. The type that hacks will have 'water resistant' on the dial." But Mike/"mmounce" says, "I have 3 that all hack. One of them is an early model with water 'proof' instead of 'resist' on the dial and caseback and it hacks also." So it's unclear which specific models of the 6105 divers hack and which do not, though both exist.

Seiko 6105s were very popular with American GIs in Vietnam, as the watch had a reputation for ruggedness and durability in the harsh Vietnamese combat environment. Although not a "military issue" watch, it was readily available at the local PX.

Ever since Seiko started putting out its line of hardcore diver's watches, folks have been using them for all sorts of extreme situations.

Here's an anecdote from S&C Forum contributor John Miller about what he and his 6105 went through:

My trusty 1966 6105 Diver has withstood one Alaskan plane crash (small plane) after being left in the woods "lost" for 6 months after it broke from my wrist and flew out on crash impact until we could come back and salvage the aircraft in the spring. (Lived in Alaska 24 years) Another was our helicopter went down in the North Atlantic in the late 70's during a storm and a trip to the offshore oil platforms, we were in a raft for 7 hours in heavy seas and freezing spray. A refinery explosion in France in the 80's when several people close by were killed and my Seiko once again became airborne and was found several hundred feet away. I just had in restored by Eric in Seattle of EMW and it's looks like a new watch. Any way I guess that's tough..............
The 6105s and the 6309s that follow them were popular especially among American soldiers who bought them cheap from the PX.

According to a S&C Forum contributor, the 6105 divers were issued to one of the U.S. Navy Seal teams in the 1960s.

In the 1979 Francis Ford Coppola film "Apocalypse Now," Captain Willard (played by Martin Sheen) was an Airborne Army Ranger who wore a 6105 diver.

Scubawatch trivia:
Capt. Willard, played by actor Martin Sheen in the movie Apocalypse Now, wore a Seiko 6105 dive watch.